Safety device for steam-boilers.



y1/m 7] gvewtor Patented 0013. 31, 1911.

III' I J J BARRY & P L STREET SAFETY DEVICE FOR STEAM BOILERS.

APPLIUATION FILED 1111115, 1910.

Attorneys UNITED STATES PATENT OFFICE.

JOHN J. BARRY AND FRANCIS L. STREET, OF NEODESHA, KANSAS.

SAFETY DEVICE FOR STEAM-BOITIERS.

Specification of Letters Patent.

Patented Oct. 31, 1911.

vention relates more particularly to that class of safety devicesdesigned to prevent bursting of the boiler when the water level thereinis abnormally low.

It is one aim of the present invention to overcome the disadvantages ofdevices of this' class now in use, such devices being now soconstructedas to become readily clogged with sediment or scale and liable not toperform their proper function when the water level in the boiler becomesabnormally low.I Such devices, usually, embody a fusible plug but are soconstructed that sediment and? scale may form and become incrusted uponthe plug and completely close the passage inf which the plug ispositioned, so that while,

when the water level in the boiler becomes abnormally low, the plug mayfuse, the passage in which it is positioned, will not be opened inasmuchas the sediment and scale caked in the passage is not affected by theheat. i

It is the aim of the present invention, therefore, to so construct thedevice that the passage in which the plug is positioned will be keptfree from sediment and scale. y

A further aim of the present invention is to so construct the devicethat the fusing of the plug will serve to open the passage in which theplug is positioned and allo7 steam to flow from the boiler, throughapipe discharging into the re box. Thus, means is provided forautomatically extinguishing the ire in the fire box when the water levelin the boiler becomes abnormally low.

Vith the above and other objects in view, the invention resides in thegeneral `con-4 struction and arrangement of parts substan-` tially asset forth in the appended claims andillust-rated in the accompanyingdraw-y ings, in which,

Figurel is a vertical longitudinally sectional view through a portion ofa locomotive boiler illustrating the arrangement of the inventiontherein. Fig. 2 is a detail vertical sectional view through the device.Fig. 3 is a vertical transverse sectional view through the portion ofthe boiler and fire box shown in Fig. 1 of the drawings. Fig. 4 is aview similar to Fig. 3 illustrating a slight modification in thearrangement of parts of the device.

In the drawings, the numeral 5 indicates the boiler shell and 6 theusual steam dome at the top thereof.

The numeral 7 indicates the crown sheet of the lire box 8 and thenumeral 9 designates the usual fountain which is supplied with steam bya pipe 10 leading thereto from the steam dome 6. 4

The safety device embodying the present invention includes a casing 11having its lower end reamed out as at 12 to afford a comparatively thinbottom wall 13 at the lower end of the casing. The said lower end of thecasing is exteriorly threaded as at 14C and is fitted in an openingformed in the crown sheet 7' of the lire box. Within the casing 1l uponthe bottom wall 13 thereof, there is formed a seat 15 upon which fitsthe lower end of a fusible plug 16. The body of this plug is of the samediameter as the interior of the casing and fits snugly theren wit-hin. Asteam discharge pipe 17 leads rearwardly from the casing 11, through therear head of the boiler shell, and terminates at the door of the firebox, its end being presented forwardly so that steam passing through thepipe will be discharged directly into the fire box. This pipe 17 ishowever normally closed, at its end which connects with the casing 11,by the fusible plug 16. The seat 15 within the casing is formed with asmall opening 18 which opens into a cham-V ber 19 projecting'from thecasing 11 and closed by a cap 20. Normally, the water within the boiler5 covers the casing 11 or at least that portion thereof in which theplug 16 is fitted but, should the water level fall to such degree as toexpose the casing directly to the heat of the fire box, the plug 16 willbe fused and will flow through the opening 18 into the chamber 19provided for its reception.

A tubular bushing 21 is threaded into the upper end of the casing and atits lower end bears upon a shoulder 22 formed kupon the plug 16 byreducing its upper end. A steam supply pipe 23 leads from the fountain 9to a pipe 24e threaded at its lower end to the upper end of the bushing21. This pipe 24k is provided at its upper end with a valve 25.

As heretofore stated, it is one aim of the present invention to providemeans for preventing the accumulation of sediment and scale upon theplug, and with this end in View, the bushing 21 is formed with anopening 26 in registration with a small opening 27 formed through thewall of the casing 11. The opening 27 is located at a poi-nt coincidentwith or immediately above the upper end of the plug 16 and leading fromthe casing is a vent pipe 28 between which and the interior of thecasing the opening 27 establishes communication. This vent pipe 28 leadsthrough the boiler' shell 5 and owing to this fact it is preferablyextended laterally from the casing. It will be observed from aninspection of F ig. 8 of the drawing that this vent pipe is straightthroughout its entire length so that a wire or other suitable implementmay be inserted therein for the purpose of removing any sediment orscale which might in time ac-p cumulate therein.

It will be observed that the steam dis-l charge pipe 17 leads rearwardlyfrom the casing 11, through the rear head of the boiler shell, anddownwardly and into the fire box 5.

The operation of the device is as follows: The device is normallycovered or partly covered by the water in the boiler 5. However, shouldthe water level in the boiler become abnormally low, and the crown sheet7 heated to an abnormal degree, the plug 1G will be fused and will flowthrough the open! ing 18 and into the chamber 19. Vhen this occurs,steam is allowed to flow from the steam supply pipe through the casing11 and out through the discharge pipe 17 by which pipe it is directedinto the fire box and extinguishes the iire therein, thus avoiding thebursting of the boiler. Under normal conditions, the steam entering thecasing by way of the supply pipe 23, will escape, very slowly, however,through the vent opening and through the vent pipe 28. Inasmuch as thisvent opening 27 is located at a point immediately above the upper end ofthe plug 16, the jet of steam issuing through the opening will serve todraw into the opening and through the pipe 28, any sediment or scalewhich would otherwise collect upon the upper end of the plug 16. It willbe understood of course that the pipe 28 is at all times open to theatmosphere. It will be further understood at this point that inasmuch asthe pipe 28 is straight and opens through the boiler shell, a wire maybe inserted through the pipe and the opening 27 and into the casing 11at a point immediately above the plug 16 for the purpose of removingaccumulations from the pipe 28 or for breaking up any crust or scalewhich may have formed or accumulated upon the upper end of the plug 1G,during a period of disuse. Furthermore, by opening the valve 25, a wireor like cleaning implement may be inserted down through the pipe 24f forthe same purpose.

In Fig. 4, of the drawing, the numeral 28a indicates a -vent pipecorresponding to the pipe 28 shown in F ig. 3 of the drawings, and thispipe opens through the boiler shell at one side thereof. Also, in thesaid Fig. 4, the numeral 17 u indicates a pipe corresponding to the pipe17 shown in Figs. 1 and 2 of the drawings, but, this pipe, instead ofdischarging into the lire box of the boiler, extends laterally from thecasing 11 and opens through the boiler shell at that side opposite theside through which the pipe 28@L opens.

Vhat is claimed is:

1. In a device of the class described, a casing, a steam supply pipeopening into the casing, a steam discharge pipe leading from the casing,a fusible plug fitted in the casing and closing communication betweenthe steam supply and discharge pipes, a seat within the casing for theplug, and a chamber upon the casing for receiving the fused plug, theseat for the plug being formed with an opening in communication with thechamber.

2. In a device of the class described, a casing, a steam supply pipeopening into the casing, a steam discharge pipe leading from the casing,a .fusible plug fitted in the casing` and closing communication betweenthe steam supply and discharge pipes, and a vent pipe leading from thecasing at a point immediately above the upper end of the plug.

3. In a device of the class described, a casing, a steam supply pipeopening into the casing, a steam discharge pipe leading from the casing,a fusible plug fitted in the casing and closing communication betweenthe steam supply and discharge pipes, and a straight vent pipe leadingfrom the casing at a point immediately above the upper end `of thefusible plug.

1. In a device of the class described, a casing, a steam discharge pipeleading from the casing, a plug fitted in the casing and closing thesaid steam discharge pipe, a bushing threaded into the casing andbearing upon the plug, a steam supply pipe connected to the bushing, anda vent pipe leading from the casing in a plane with the upper end of theplug.

5. In a device of the class described, a casing, a steam supply pipeopening into the casing, a steam discharge pipe leading from the casing,a fusible plug fitted in the casing and closing communication betweenthe steam supply and discharge pipes, and

means for exhausting steam from the casing at a point directly above theupper end of the said fusible plug.

6. In a device of the class described, the combination with a boiler`and its re box, of a casing fitted upon the Wall of the re box, a steamsupply pipe leading from the boiler to the casing, a steam dischargepipe leading from the casing and into the fire box, a fusible plugfitted in the casing and closing communication between the steam supplyand discharge pipes.

7 In a device of the class described, a casing, a steam discharge pipeleading from the casing, a fusible plug tted in the casing and closingthe said steam discharge pipe, a

steam supply pipe leading into the casing, above the plug, a vent pipeleading from the casing in a plane With the upper end of the plug, and achamber upon the casing for receiving the fused plug, the chamber beingJOHN J. BARRY. FRANCIS L. STREET.

Witnesses:

F. B. KIMBALL, C. M. KIMBALL.

Copies of this patent may be obtained for ve cents each, by addressingthe Commissioner of Patents, Washington, D. C.

